Satellite communication in amateur radio lets licensed operators reach way beyond what you can do with traditional ground-based signals. Operators use satellites in low Earth orbit or higher to send and receive voice, data, and digital signals across continents, and honestly, you don’t need a ton of fancy gear to get started. You transmit on one frequency—the uplink—and receive on another—the downlink—using a satellite as a repeater up in space.
This kind of communication blends radio skills with a bit of orbital mechanics, frequency coordination, and some antenna tracking know-how. Volunteer organizations build and maintain many amateur satellites, and they usually keep them running reliably. Whether you’re swinging a handheld antenna or letting a computer track things for you, you’ll need good timing, some planning, and a sense of when satellites will pass overhead.
If you’re looking to level up your radio skills, satellite operation gives you a hands-on way to try out advanced communication techniques. It’ll introduce you to satellite types, different operating modes, and a bunch of frequency bands, plus the challenge of actually making a contact during a short satellite pass.
Fundamentals of Satellite Communication in Amateur Radio
Operators use orbiting satellites to relay radio signals between stations that can be thousands of kilometers apart. These systems push ham radio’s range far past what’s possible with ground-based signals, and you can even talk to the International Space Station.
How Satellite Communication Works
Amateur radio satellites basically act as repeaters in space. They pick up an uplink signal from a ground station, process or amplify it, and send it back down on a downlink frequency.
Most amateur satellites fly in low Earth orbit (LEO) and zip overhead in just a few minutes. You have to time your transmissions to catch these short windows.
Tracking software or online prediction tools show you a satellite’s path, elevation, and Doppler shift. That Doppler shift means the frequency changes a bit as the satellite comes toward you or moves away, so you’ll need to tweak your settings during a contact.
Some satellites use FM mode for simple voice exchanges. Others support SSB or digital modes if you want to get a bit fancier.
Benefits for Amateur Radio Operators
Satellite communication lets you make long-distance contacts without worrying about ionospheric conditions. It’s pretty predictable, since you can plan passes ahead of time.
You also get to try out different modes—voice, Morse code (CW), or digital data. Some operators experiment with APRS for packet messaging through satellites.
You don’t need a massive setup. A handheld transceiver and a small directional antenna are enough to work many satellites, so portable operation is totally doable.
You might even contact astronauts on the ISS or chase down some satellite-specific awards if you’re feeling ambitious.
Key Terminology and Concepts
Uplink, the frequency you use to send signals from your station up to the satellite.
Downlink, the frequency the satellite uses to beam signals back down to Earth.
LEO (Low Earth Orbit), satellites that orbit from about 160 to 2,000 km up, passing by quickly.
GEO (Geostationary Orbit), satellites that hang over one spot on Earth, giving you constant coverage in their area.
Doppler Shift, the frequency change you’ll hear as the satellite moves relative to you.
OSCAR, which stands for “Orbiting Satellite Carrying Amateur Radio,” a label for amateur satellites.
Knowing these terms helps you plan, track, and actually complete satellite contacts more efficiently.
Types of Amateur Radio Satellites
Amateur radio satellites come in different orbits, altitudes, and coverage areas. Each type brings its own communication opportunities, equipment needs, and operational quirks. The way they’re built and where they orbit affects how long and how often you can use them.
Low Earth Orbit (LEO) Satellites
LEO satellites orbit somewhere between 300 km and 2,000 km up. They move fast, circling the globe in about 90 to 120 minutes. That gives you short communication windows, sometimes just 5–15 minutes per pass.
They’re popular because you don’t need complicated equipment. Most folks use a dual-band VHF/UHF handheld transceiver and a small directional antenna. Tracking apps or software help you know when a pass is coming.
LEO satellites often have FM cross-band repeaters or linear transponders. FM satellites are great for beginners, while linear transponders allow several people to make contacts at once. Think AMSAT fleet or the ISS amateur station for examples.
Because they’re closer to Earth, you get stronger signals than with higher satellites, but you’ll need to adjust for Doppler shift more often. Be ready to tweak your frequencies as the satellite moves.
High Earth Orbit (HEO) and Geostationary Satellites
HEO satellites go much higher, sometimes tens of thousands of kilometers out. Some follow elliptical paths, so they linger over a region for hours.
Geostationary satellites stay fixed over one spot above the equator, about 35,786 km up. They cover the same area all the time, so you don’t need to chase them across the sky.
Amateur geostationary satellites are rare, but they’re a big deal. You’ll need more advanced gear—high-gain antennas, precise pointing systems, and often microwave-band transceivers.
These satellites work well for scheduled contacts, experiments, or emergency comms. But honestly, the cost and technical demands mean not everyone can use them.
CubeSats and PocketQubes
CubeSats are tiny, standardized satellites built in 10 cm cubes, usually weighing around 1–1.3 kg each. PocketQubes are even smaller, using 5 cm cubes. They often hitch rides as secondary payloads on rockets.
Many CubeSats and PocketQubes carry amateur radio gear. They might work as FM repeaters, digital data relays, or platforms for trying out new communication modes.
Their small size makes them affordable for universities, research groups, or amateur clubs to build and launch. But with small antennas and limited power, their signals can be weaker, and they don’t last as long.
You can often track several CubeSats in a single day, since they share similar low Earth orbits. That gives you more chances to make contacts and try different modes.
Communication Modes and Frequency Bands
Amateur radio satellites use a mix of communication methods, depending on how they’re built and what they’re for. Each one has its own style, equipment needs, and typical frequencies—usually in the VHF and UHF bands. Operators pick the mode that matches their skills, license, and gear.
FM Voice and SSB
FM voice is probably the most common way to use satellites. It’s a lot like talking on a local repeater, but the uplink and downlink use different bands, like 2 m (VHF) for uplink and 70 cm (UHF) for downlink.
People call FM satellites “easy-sats” since you can work them with just a handheld radio and a small directional antenna. You’ll need to tune carefully during a pass, especially on UHF, to keep up with Doppler shift.
Single Sideband (SSB) is used on linear transponder satellites. With SSB, several stations can use a range of frequencies at once, which is more efficient for longer or competitive contacts. It does take more skill to tune and align your signals.
Morse Code (CW) Operations
A lot of linear transponder satellites support Morse code (CW). CW is super efficient because it uses a very narrow bandwidth, so you can still hear signals even if they’re weak. That makes it great for low-power operation.
Operators usually use SSB receivers to copy CW signals from satellites, and you’ll need to adjust your frequency as the pass goes by. CW contacts often use the same bands as SSB, like 70 cm uplink / 2 m downlink or vice versa.
CW only sends tones, so you can decode it by ear—no special gear required. But you do need to tune carefully, since even a small error can make the tone tough to copy.
Digital Modes and Packet Radio
Digital modes let satellites carry text, images, or telemetry. Packet radio with the AX.25 protocol is common, especially on satellites with digipeaters. These systems store and forward short bursts of data between stations.
Some satellites use VHF uplink / UHF downlink for packet, while others stick to UHF for both. Operators often use software to track passes and auto-tune for Doppler shift.
Digital operation can include APRS (Automatic Packet Reporting System), which sends position and status data. This comes in handy for tracking mobile stations or relaying quick messages through satellites that act as space-based repeaters.
Essential Equipment for Satellite Operations
You’ll want equipment that can handle the right frequency bands, track satellites as they move, and deal with transmitting and receiving at the same time. The right setup boosts your signal, cuts down interference, and helps you get the most out of those short satellite passes.
Transceivers and Handheld Radios
A dual-band VHF/UHF transceiver is the go-to for satellite work. Lots of operators just use handheld transceivers (HTs) for portable setups, especially with LEO satellites.
If you want more options, a mobile or base transceiver with adjustable power gives you better control over your signal. Radios that let you change frequency quickly are key for keeping up with Doppler shift.
Some radios come with built-in satellite modes, making it easier to handle split-frequency operation. You can store uplink and downlink frequencies in memory pairs, which saves time during a contact.
Directional Antennas and Rotators
Satellite signals can be pretty weak, so a directional antenna helps you focus your signal where it counts. Handheld Yagi antennas are popular for portable use, while fixed antennas with higher gain work well for home stations.
Antenna polarization matters for signal clarity. Operators often use antennas with switchable or circular polarization to cut down on fading from signal rotation in the atmosphere.
If you’re setting up at home, azimuth-elevation rotators can automate antenna tracking. They follow the satellite across the sky, which boosts your signal and saves you from constant manual tweaks. Portable users usually track satellites by hand, guided by pass prediction apps or software.
Full-Duplex Operation
Full-duplex capability lets you transmit and receive at the same time on different frequencies. This is huge for monitoring your return signal in real time, so you can adjust your aim, power, or frequency as needed.
Some handheld transceivers pull off limited full-duplex if you pair them with a second receiver. More advanced mobile or base transceivers handle it all inside the box, so you don’t need extra gear.
If you don’t have full duplex, you’ll have to switch back and forth between transmit and receive, which means you might miss replies. For busy passes or contests, full duplex really helps you snag more contacts.
Tracking and Predicting Satellite Passes
If you want to know when a satellite will be in range, how long you’ll have to work it, and which frequencies to use, you’ll need accurate satellite tracking. Getting these details right means more chances to make contacts and better communication overall.
Satellite Pass Prediction Tools
Operators use software and online tools to predict satellite passes. These tools use TLE (Two-Line Element) data to figure out when a satellite will pop above the horizon.
Popular picks include AMSAT Online Pass Predictions, Gpredict, and Ham Radio Deluxe. You’ll get real-time maps, elevation graphs, and azimuth headings.
Most platforms let you enter your location by latitude and longitude or Maidenhead grid square. That way, predictions are spot on for where you are.
Features often include:
- Next pass time and how long it’ll last
- Maximum elevation (in degrees)
- Azimuth start and end points
- Co-visibility between two spots for scheduled contacts
You’ll want to keep your orbital data updated, since satellite paths can drift over time.
Understanding Doppler Shift
When a satellite moves toward or away from a station, its signal frequency changes a bit. You’ll notice this Doppler shift more at higher frequencies, like VHF or UHF.
As the satellite gets closer, the frequency you receive jumps up. When it moves away, the frequency drops. Both uplink and downlink signals shift like this.
Most tracking software will handle Doppler correction automatically if you hook it up to a compatible transceiver. If you don’t have that, you’ll need to tweak the frequencies by hand while the satellite passes.
The shift can run several kilohertz during a single pass. With narrowband modes, even a tiny error can mess up your signal, so real-time adjustments matter.
Timing and Planning Contacts
To make contact, you have to know exactly when a satellite will appear and disappear. Passes usually last somewhere between 5 and 15 minutes, depending on the orbit and how high the satellite gets above the horizon.
If you catch a pass with a higher maximum elevation, you’ll keep the satellite in view longer. You also dodge a lot of atmospheric interference. Low passes near the horizon don’t last as long and can get blocked by trees or buildings.
Operators usually plan ahead by checking:
- Pass time and duration
- Maximum elevation
- Footprint coverage to make sure both stations are in range
Good timing helps you avoid stepping on other operators, which can get tricky on busy satellites.
Making Successful Satellite Contacts
If you want clear communication through amateur radio satellites, you need to nail your timing, set up your gear right, and stick to good operating habits.
You have to know when the satellite will fly overhead. You’ll need to tune for Doppler shift and make the most of those brief windows.
Establishing Satellite Contacts
A contact starts with knowing when and where the satellite will be within reach. Tracking software or apps give you predictions—elevation, direction, and how long you’ll have.
Most operators use dual-band radios that let them transmit and receive at the same time. That way, they can hear the other station’s audio while they talk.
During the pass, you’ll need to keep adjusting your frequency for the Doppler shift, especially on UHF. It takes a lot of tiny, quick changes to keep the signal clear.
A lot of folks start out by listening to a few passes before they try transmitting. You can pick up on active frequencies, learn call signs, and get a sense of the timing.
Basic steps for initiating a contact:
- Make sure you have the right satellite frequency and mode (FM or linear).
- Wait until the satellite rises above the horizon.
- Call out briefly with your call sign and grid locator.
- Log your contact—note the time, frequency, and satellite name.
Operating Etiquette and Best Practices
Satellite passes are short—sometimes less than 15 minutes. You have to keep your communication clear and to the point.
Skip the long conversations. The usual exchange is just your call sign, grid square, and a quick acknowledgment. That way, more people get a shot during the pass.
Always listen before you transmit. You’ll avoid interfering and make sure the frequency’s clear. It also helps you spot ongoing QSOs so you don’t talk over anyone.
Use phonetics for your call sign. It really helps when signals fade or there’s background noise. For example, “Kilo Charlie One Alpha Bravo” comes through much clearer than just “KC1AB.”
Log your contacts right away. It keeps your records straight and helps if you’re chasing awards, like satellite operating certificates.
Overcoming Common Challenges
You’ll probably run into signal fading if you have trees, buildings, or hills in the way. I usually grab a directional antenna and try to stand somewhere open, which really helps reception.
Doppler shift sometimes distorts the audio, and if you don’t fix it, it just gets worse. I tweak the receive and transmit frequencies during the pass, and that keeps things sounding clear.
When a pass gets crowded, interference makes things tricky. Honestly, a little patience and some well-timed transmissions usually get me through without stepping on anyone else.
If you’re running a portable setup, battery life can be a headache. I make sure everything’s charged up and toss a few spares in my bag so I don’t miss out on later passes.
Environmental noise is another pain—wind, city RF, all of it. I use a headset mic and shield my gear from the wind, and that definitely boosts audio quality.